Dielectric and Piezoelectric Properties of BiFeO3 from Atomistic Simulations

MÓNICA GRAFF; SEPLIARSKY, MARCELO; MACHADO, RODRIGO; STACHIOTTI, MARCELO GABRIEL

Porto

Congreso; Congreso; 13th European Meeting on Ferroelectricity; 2015

Recently we have investigated the structural and polar properties of BiFeO 3 at finite temperature using an atomistic model fitted to first-principles calculations 1. Molecular dynamics simulations showed a directtransition from the low-temperature R3c ferroelectric phase to the Pbnm orthorhombic phase without evidence of any intermediate bridging phase between them. The Pbnm high-temperature phase wascharacterized as antiferroelectric by the presence of two sublattices with opposite polarizations, and the characteristic double-hysteresis loop under the action of an external electric field 1. One advantage of ourtheoretical approach is the possibility to calculate single crystal properties, which are important to determine the anisotropy of material properties. In this work we use the developed model to investigatedielectric and piezoelectric properties of BiFeO3 as function of the temperature and strain. To this purpose, we calculate for each phase the coefficients along the corresponding crystallographic directions